Percutaneous sheath introduction sets are commonly used in the placement of Swan Ganz catheters, transvenous temporary pacing electrodes, subclavian dialysis catheters, and when a large bore intravenous catheter is needed for rapid administration of large volumes of fluid. A blood vessel is cannulated with a needle and a guidewire is inserted through the needle into the vessel. The needle is then withdrawn and a catheter is then placed into the vessel over the guidewire and the wire is then removed.
While successful catheterization of the vessel is usually achieved in most patients, multiple attempts per patient are sometimes necessary with a concomitant rise in complication rates. One cause of failure of catheterization is the dislodging of the needle from the vessel once puncture is identified by blood return in the syringe. This can result from movement of the needle while the syringe is being removed, when one attempts to stem the flow of blood from the needle hub or when the guidewire is being directed toward the needle for insertion. Once the needle is dislodged from the lumen of the blood vessel, the wire cannot be inserted.
It is an object of the present invention to combine the syringe and guidewire into one unit. This would have the advantage of lessening the chance of dislodging the needle from the vessel by eliminating the need to remove the syringe from the needle, to cover the hub of the needle to stem blood loss, and to reach for and direct the guidewire into the needle. The present system would also eliminate one of the possible sources of air embolism occurring during this procedure, a rare but disastrous complication of central venous catheterization.
In the present system, a hole is made in the middle of the plunger of the syringe and the flexible end of the guidewire is threaded through this hole so that a variable amount of wire is in the cylinder of the syringe. During the procedure, it is necessary for the syringe portion of the apparatus to be able to maintain both positive and negative (suction) pressures. Pressures are maintained by a rubber end of the plunger and a tapered luer fitting on the opposite end. When puncture of the vessel is successful, the seal at the luer fitting is broken, and the guidewire is advanced the desired distance into the vessel.
A U.S. Pat. No. 4,274,408, to Nimrod, issued Jan. 23, 1981, describes a method for guidewire placement and syringe for inserting a catheter guidewire into a blood vessel. This Nimrod disclosure relies on a ball or diaphragm to seal the opening containing the guidewire to enable the device to create both suction and pressure. The Nimrod plunger is used to break the seal or dislodge the ball seal.
In the present device, the guidewire is totally encapsulated and a fixed volume is trapped in the syringe. Consequently, no seal, as required by Nimrod, is needed. Thus, the present disclosure involves a simpler syringe construction which allows repeated uses since there is no sealing mechanism that is destroyed when the syringe is used. The present disclosure also reduces the possibility of contamination of the guidewire, and allows adaptability of either a straight end guidewire or a J-end as will be explained.
Other objects and features of the invention will be evident in the following description and claims in which the principles of the invention are set forth together with details to enable those skilled in the art to practice the invention, all in connection with the best mode presently contemplated for the invention.